const CACHE_NAME = 'version-1';
const urlsToCache = [ '/', '/index.php', '/assets/css/custom.css', '/assets/js/main.js' ];

self.addEventListener('install', event => {
    event.waitUntil(
        caches.open(CACHE_NAME)
            .then(cache => {
                console.log('Opened cache');
                return cache.addAll(urlsToCache);
            })
    );
});

self.addEventListener('fetch', event => {
    event.respondWith(
        caches.match(event.request)
            .then(response => {
                if (response) {
                    return response;
                }
                return fetch(event.request);
            })
    );
});

self.addEventListener('activate', event => {
    const cacheWhitelist = [];
    cacheWhitelist.push(CACHE_NAME);

    event.waitUntil(
        caches.keys().then(cacheNames => Promise.all(
            cacheNames.map(cacheName => {
                if(!cacheWhitelist.includes(cacheName)) {
                    return caches.delete(cacheName);
                }
            })
        ))
    )
});